arm64: dts: st: add Hardware debug port (HDP) on stm32mp25

arm64: dts: st: add Hardware debug port (HDP) on stm32mp25

Add the hdp devicetree node for stm32mp25 SoC family

Keep the node disabled as HDP needs the pinctrl SoC configuration to be
able to output its mux output signal outside of the SoC, on the SoC pad.
This configuration is provided in the board dtsi file through 'pinctrl-*'
properties as well as HDP mux configuration.
Thus, if needed, HDP should be enabled in board dtsi file.

Signed-off-by: Clément Le Goffic <clement.legoffic@foss.st.com>
Link: https://lore.kernel.org/r/20250711-hdp-upstream-v7-6-faeecf7aaee1@foss.st.com
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>